Publication Number: FHWA-HRT-09-005

Communication Product Updates

Compiled by Zachary Ellis of FHWA's Office of Corporate Research, Technology, and Innovation Management

Below are brief descriptions of communications products recently developed by the Federal Highway Administration's (FHWA) Office of Research, Development, and Technology. All of the reports are or will soon be available from the National Technical Information Service (NTIS). In some cases, limited copies of the communications products are available from FHWA's Research and Technology (R&T) Product Distribution Center.

When ordering from NTIS, include the NTIS publication number (PB number) and the publication title. You also may visit the NTIS Web site at www.ntis.gov to order publications online. Call NTIS for current prices. For customers outside the United States, Canada, and Mexico, the cost is usually double the listed price. Address requests to:

Address requests for items available from the R&T Product Distribution Center to:

For more information on R&T publications from FHWA, visit FHWA's Web site at www.fhwa.dot.gov, the Turner-Fairbank Highway Research Center's Web site at www.fhwa.dot.gov/research/tfhrc/, the National Transportation Library's Web site at http://ntl.bts.gov, or the OneDOT information network at http://dotlibrary.dot.gov.

In recent years, FHWA has researched certain novel intersection designs as a means to improve intersection safety while meeting the often conflicting demands to increase capacity, decrease travel time, and minimize the cost of new infrastructure. One of these designs, the displaced left-turn lane intersection (DLT), is in the early stages of deployment in the United States. This report describes FHWA research on signing and marking of DLT intersections—also known as continuous flow intersections.

The DLT is an at-grade intersection that is intended for areas where there is a large volume of left turns and heavy through volume. The DLT design uses two- or three-phase traffic signals at the junction of two roads, while still providing at-grade protected left turns. In DLT intersections, left-turning traffic crosses over opposing lanes to the left side of the roadway well before the main intersection. Left-turning vehicles then travel on a new roadway parallel to the opposing lanes and execute the left turn with a signal simultaneously with the through traffic at the main intersection. Timing of the signals at the crossover points and at the main intersection helps to ensure that vehicles, whether through or turning, stop just once at the intersection.

Several studies have shown the benefits of the DLT design over other signalized intersection designs in terms of increased capacity and efficiency of land use. Because a DLT uses a two-phase signal, it results in less delay, fewer pollutants, and lower fuel consumption than conventional at-grade intersections with three or more signal phases.

The summary report is available at www.fhwa.dot.gov/research/topics/safety/intersections/index.cfm. Printed copies also are available from the FHWA Product Distribution Center.

FHWA's Turner-Fairbank Highway Research Center (TFHRC) in McLean, VA, is the Nation's premier highway research and development facility. TFHRC coordinates and conducts an ambitious program of innovative highway research and development to address critical needs of the national highway system. This brochure provides an overview of TFHRC's research and development offices and a historical timeline.

As a national leader in transportation research, FHWA works with the U.S. Department of Transportation and partners in State and local government, industry, and professional organizations to develop and deliver a comprehensive nationally coordinated research and technology program. FHWA also collaborates with other institutions, such as the National Academy of Sciences, university transportation centers, national laboratories, and international highway research laboratories and communities to support this national transportation research program.

At TFHRC, FHWA's engineers, scientists, and psychologists conduct advanced and applied research to create innovative solutions that improve Americans' quality of life. By developing advanced technologies and techniques and implementing systems and simulation tools, TFHRC focuses on preventing congestion, improving mobility and roadway safety, reducing highway crashes and related fatalities, and improving infrastructure performance. Through FHWA's three research and development offices—Infrastructure, Safety, and Operations—along with the Exploratory Advanced Research Program, the agency is working to meet the transportation challenges of today and the future.

The brochure is available at www.fhwa.dot.gov/publications/research/general/08066/index.cfm. Printed copies are available from the FHWA Product Distribution Center.